Telephone system



Jan. 12, 1932. w. \NHITNEY 7 TELEPHONE SYSTEM Filed April 30, 1930 3 Sheets-Sheet l Z5 1 LD B) I ATTORNEY Jan. 12, 1932. w WHITNEY 1,840,376

TELEPHONE SYSTEM Filed April 50, 1930 5 Sheets-Sheet 2 9 4 A ATTORNEY Jan. 12, 1932. w. WHITNEY TELEPHONE SYSTEM Filed April 30, 1950 3 Sheets-Sheet 3 /l/E/V70/? W WHITNEY U- I o ATTORNEY W Q W II If Patented Jan. 12, 1932 UNITED: STATES PATENT orncs WILEY WHITNEY, or EAST'ORANGE, NEW JERSEY, ASSIGNOR TO BELL TELEPHONE LABORATORIES, INCORPORATED, on NEW YORK, N. 2., A CORPORATION on NEW YORK TELEPHONE SYSTEM Application filed April 30,

a signal to'notify the operator that she has used a cord circuit unsuited for connection to the line with which she has made connection. 7

Due to the rapid growth of toll service and the desire of the telephone operating companies to handle this service with the same speed as local service it is becoming expedient to place toll trunks before ,A operators. 'Then, since the toll trunk requires much higher transmission cord circuits than does the ordinary local line, such A operators"psitions are equipped with toll cords in addition to the usual A cords. To prevent the establishment of a connection from a local line over an A cord to a toll trunk a'preemptory signal in the form of a flashing lamp in the cord circuit is given to attract the operators attention to her error.

The drawings consist of four sheets of circuit diagrams illustrating the present invention. Fig. 1 shoWs a cord cireuitspecially adapted for use with toll switching trunks; Fig. 2 shows an ordinary A operators cord circuit; and F igs'. 3 and 4 show two forms of toll switching trunk with which the cord circuit of Fig. 1 is adapted to cooperate. 3

. The toll switching trunks of Figs. 3 and 4 arecircuits that terminate at a position where the operator handles ordinary traffic between subscribers and traffic originating at a subscribers station and directed from there to a toll point. Since it is intended that such latterconnections shall be handled over high quality'transmission circuits the present inye'ntion provides means to notify the operator 1930. Serial No. 448,495.

when she has by mistake used the wrong cord for establishing such a connection.

We will therefore first describe the results of connecting the cord circuit of Fig. 2 to the trunk circuit of F ig. 3. When plug 1 is inserted injack 2 a circuit is established from ground, contacts 3 and 4 of interrupter 5, conductor 6, normal contacts of the upper armature of relay 7, ring of jack 2, ring of plug 1, supervisory relay 8 to battery. In the meantime a circuit is established from battery, supervisory lamp 9, resistance 10, sleeve of plug 1, sleeve of jack 2, normal contacts of the upper armature of relay 11, lower low resistance winding of relay 12 to round. Supervisory lamp 9 will be energized in this circuit but during the energization of supervisory relay 8 will be shunted through resistance 13 so that it will not glow. However, as interrupted functions the contact at will be periodically moved away from contact 3 and into connection with contact 14, which leading to a battery connection will cause the deenergization of supervisory relay 8 and consequently will cause supervisory lamp 9 to flash. The operator noting the flashing of lamp 9 will take down the connection established through the cord circuit of Fig. 2 and substitute the cord circuit of Fig. 1.

The insertion of plug 15 into the jack of the calling subscribers line will cause the energization of relay 16 through the usual ground connection found on the sleeve of the subscribers line jack. Relay 1? will be energized through the front contact and upper outer armature of relay 16 by ground either at the inner normal contact of the operators listening key 18 or the inner upper armature and back contact of relay 19. Relay 17-c0nnects ground and battery to the windings of relay20 and talking battery is thus connected through the back contacts of relay 19 to the calling subscribers line. An energizing circuit for signal lamp 21 is established through resistance 22 and the front contact and inner upper armature of relay 16 to ground but the signal lamp 21 is prevented from glowing at thistime due to a shunt circuit established through resistance 23, armature and contact 30 armature and front contact of relay 19, tip

of relay 20, back contact and upper armature of relay 24 to battery.

It will be assumed that at this point plug 25 isinserted in ack 2. A circuit will then be established through the lower low resistance winding of relay 12 in series with relay 26 and marginal relay 27. All three relays will become energized. Relay 26 will extend aground connection through the contacts of the lower armature ofrelay" 16 to energize relay 19 and this latter relay will look through its inner lower armature and front contact to this same ground. Relay 24 becomes energized to transfer the controlof signal 21 to relay 27. Since relay 27 is at this instant energized lamp 21 will glow.

If itis assumed. hat the operators key 18 is now operated then relay 17 will be released and the windings of relay 20 will bebridged across the tipand ring of plug 25. This results in the establishment of a circuit from contact f interrupter 5, conductor 6, normal contacts ofthe upper armature of relay 7, ring of jack 2, ring of plug 25, front contact and outer lower armature of relay 19, back contact and lower armature of relay 17, lower winding of relay 20, back contact;

andupperouter armature of relay 17, upper winding ofrelay 20, upper'inner armature and, back contact of relay 17, upper outer of plug 25, tip of jackr2, upper left hand winding-of repeating coil 28, upper winding of relay 29 to ground. .When interrupter 5. moves, to the point where contacts 4 and 14-come together then relay 29 willbecome energized. 3 'Upon the energization of relay .29 .a circuit;is= closed for the energization ,of relay 7 and this relay, locks to the front contact and upper armature of relay 12. The enerization of relay 7 substitutes the lower wind,-

ing'ofrelay 29 for the connection through in v to the calling subscriber terrupter, 5 so that talking battery is supplied through the windings of relay 29.

The energization of relay 29 also closes a circuit through the normal contacts of the lower, armature of relay 30 to the winding of relay 11. Relay 11 opens the short circuit about the upper high resistance winding of relay 12v and this causes the deenergization of marginal relay 27 and the consequent shunt-- ing of signallamp 21. 1

ince further operations of the trunk circuit of Fig. 3 and the cord circuit of Fig.1

. of the trunk circuit of Fig. 4. There is then 7 have nothing to do with the presentv inven;

tion, they will not be described. Let it. now be assumed hat plug 1 of the cordcircuit of Fig.2 is inserted in jack 31 4 established a circuit from, battery, supervisory lamp 9, resistance 10, sleeve of plug '1,

sleeve of jack 31,and low resistance winding of relay 32 to, ground. Belay32 becomes front contact of relay 32, upper armature and front contact of relay 35, winding of relay 36, upper winding of relay 37to battery. A circuitis now established from battery, supervisory relay 8, ringof plug 1, ring of jack 31, lower armature and back contact of relay 33,,lower lefthand winding of repeating coil 34, lower armature and front contact of relay 35, contacts of interrupter 38, lower winding of relay 37 to ground. Each time the contacts of interrupter 38 are closed, supervisory relay 8 attracts its armature and shunts supervisory lamp 9 sorthat this signal flashes in unison with the operation of interrupter 38. This notifies the operator that she has used the wrongcord in the trunk of Fig. 4. f J

The operator will now substitute the cord of'Fig. 1 for the cord ofFig. 2.- When plug 25 is inserted injack 31,. a circuit including relays 27, 26 and 32 in series is established. Through the operation of relay'26, relay'19 becomes operated as hereinbefore. described and the windings of relay 20 arebridged across the tip'and ring of the trunk as before. A circuit may now be traced from. battery, upper winding of relay 37, winding of marginal relay 36, normal contacts of the upper armature of relay 35, upper. winding of repeating coil 34, back contact and upperouter armature of relay 33, tip of jack 31, thence through the windings of relay 20, ringof jack 31, lower armature and back contact of relay 33, lower left hand winding of repeating coil 34, lower armature and back contact of relay 35, winding of relay 39, lower winding of relay 37 to ground. Due tothe resistance of relay 39 in this circuit, relay 36 does not operate, but relay 39 attracts its armature. Thereupon a circuit is established from ground, armature and back contact ofrelay 36, armature and front contact of relay 39, winding of relay 40 to battery and ground. fRelay .40 locks in a circuit from ground, the lower armature and front contact of relay 32, the" lower armature and front contact of relay 40, winding of relay40 to battery. Through its upper outer armature, relay 4O .shortcircuit's' the Winding of marginal relay 36 and throughthe," aux.- iliary contacts controlled by its lower armature, relay 40 short circuits the windin' of relay 39. Battery and-groundfor tall ing purposes is now supplied from the windings of relay 37 over the tip and ring of the trunk circuit and thence through the cord circuit of the calling subscriber.

The operation of relay 37 extends a connection from ground, armature and front contact of relay '37, front contact and inner upper armature of relay 40, normal contacts of the inner lower armature of relay 41, winding of relay 42 to battery. Relay 42 opens the circuit around the upper high resistance winding of relay 32 to cause the deenergization of marginal relay 27 in the cord circuit to control the supervisory signal 21.

Since further operations of the trunk circuit of Fig. 4 and the cord circuit of Fig. 1 have nothing to do with the present invention, they will not be described.

What is claimedis: V

1. In a telephone system, link circuits of different character, a trunk circuit adapted to cooperate with certain of said link circuits,

a signal device in each'of said link circuits, and means responsive to a connection between said trunk circuit and other than said certain of said link circuits for operating the signal of said connected link circuit.

2. In a telephone system, an operators position, cord circuits of different characteristics thereat, a trunk circuit appearing there at adapted to cooperate with certain of said cord circuits, and means in said trunk circuit responsive to a connection between said trunk circuit and other than said certain of said cord circuits for signaling the operator at said position.

3. In a telephone system, link circuits of different character, atrunk circuit adapted to cooperate with certain of said link circuits,

a signal device in each of said link circuits,

and means responsive to a connection between said trunk circuit and other than said certain of said link circuits for intermittentl operating the signal of said connected linli circuit.

' 4. In a telephone system, link circuits of diiferent character, a trunk circuit adapted to cooperate with certain of said link circuits, a supervisory signal in each of said link circuits, an interrupter in said trunk circuit for intermittently operating the supervisory signal of a connected link circuit, and means responsive to a connection between other than said certain of said link circuits for rendering said interrupter efiective.

In witness whereof, I hereunto subscribe my name this 28th day of April, 1930.

WILEY WHITNEY. 

